1. Technical Field of the Invention
The invention relates generally to communication systems; and, more particularly, it. relates to encoding and/or decoding of information within such communication systems.
2. Description of Related Art
Data communication systems have been under continual development for many years. One such type of communication system that has been of significant interest lately is a communication system that employs turbo codes. Another type of communication system that has also received interest is a communication system that employs LDPC (Low Density Parity Check) code. In addition, other types of communication systems operate using other types of codes such as RS (Reed-Solomon) codes. Each of these different types of communication systems is able to achieve relatively low BERs (Bit Error Rates) under appropriate conditions.
A continual and primary directive in this area of development has been to try continually to lower the error floor within a communication system. The ideal goal has been to try to reach Shannon's limit in a communication channel. Shannon's limit may be viewed as being the data rate to be used in a communication channel, having a particular SNR (Signal to Noise Ratio), that achieves error free transmission through the communication channel. In other words, the Shannon limit is the theoretical bound for channel capacity for a given modulation and code rate.
Each of these different types of codes has certain limitations and best capabilities to accommodate certain types of errors that may occur within a communication system. Oftentimes, certain of these codes are specifically selected and employed within a communication system type that suffers from deleterious effects and errors for which the code is most capable to correct. For example, some types of errors that may occur in various types of communication systems include burst errors (e.g., relatively localized in time) and/or random errors (e.g., randomly distributed across a portion of data). Turbo codes and LDPC codes are well suited to correct random errors, and RS codes are well suited to correct burst error (or impulse noise). Again, each of these various codes has certain capabilities and abilities to correct certain types of errors. However, there are instances where certain types of communication systems may undesirably experience many types of errors including both random and burst errors. Clearly, there is a need in the art for some alternative coding types that are capable to correct a wider range of error types including the capability to correct different types of errors that may occur within various locations of a communication system.